Revealing costume: nothing stops brother wearing one

• Revealing swimsuit
• Working at fair wearing skimpy skirt, or something even skimpier

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1964, from mono- + bikini , on mistaken notion that the bi- element was the Greek prefix meaning "two."

Wikipedia Word definitions in Wikipedia
The monokini , designed by Rudi Gernreich in 1964, consisting of only a brief, close-fitting bottom and two thin straps, was the first women's topless swimsuit . His revolutionary and controversial design included a bottom that "extended from the midriff ...

Wiktionary Word definitions in Wiktionary
n. The lower part of a bikini worn without the upper part (i.e., worn bare-breasted).